An apparatus includes a solid-state image pickup element that outputs video signals obtained from pixels arranged in a column direction. The apparatus also includes an amendment unit that amends an error value corresponding to a column position of the video signals according to a temperature to supply an amended error value to a subtraction unit that subtracts the amended error value for each column from the video signals. The apparatus further includes an error computing section that shields the pickup element from light or irradiates light to the pickup element at a constant rate, computes a respective average value of each of a plurality of pixel signals obtained from the pixels in a predetermined region of the pickup element, subtracts the respective average value from a respective of the plurality of pixel signals obtained from the pixels of the pickup element, and accumulates values obtained by subtractions for respective columns.